Preparation method of halogen-doped window layer and cadmium telluride solar cell

Abstract

The invention relates to a preparation method of a halogen-doped window layer and a cadmium telluride solar cell. The preparation method comprises the following steps: obtaining a powder mixture composed of cadmium halide powder and cadmium selenide powder; under the protection of nitrogen, the obtained powder mixture is put into a mold, then the mold is put into a hot pressing furnace, the hot pressing furnace is vacuumized, the air pressure in the hot pressing furnace is smaller than 0.01 Pa, inert gas is introduced for gas replacement, after gas replacement is completed, the hot pressing furnace is heated to 300-1200 DEG C at the speed of 5-15 DEG C / min, then the hot pressing furnace is pressurized, and the hot pressing furnace is cooled to the room temperature; when the air pressure in the hot pressing furnace reaches 40-100 MPa, preserving heat for 50-150 minutes under the pressure, cooling and reducing the pressure to room temperature and normal pressure, and taking out the mold from the hot pressing furnace to obtain a halogen-doped window layer material; sputtering or depositing a halogen-doped window layer material on the high-resistance buffer layer through a magnetron sputtering method or a near-space sublimation deposition method to obtain a window layer; the open-circuit voltage of the cell can be improved, and the photoelectric conversion efficiency of a cell device is effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of thin-film solar cell preparation, and in particular to a method for preparing a halogen-doped window layer and a cadmium telluride solar cell. Background Art

[0002] With the rapid development of the economy, the existence of unbalanced energy supply, low per capita resource share, aggravated environmental pollution, and unstable primary energy has forced us to accelerate the transformation to cleaner, more efficient, and recyclable energy to achieve the goal of sustainable development. Among the green energy currently being developed, solar energy has attracted people's attention due to its inexhaustible characteristics. Among them, solar cells are a device that can directly utilize solar energy, relying on the photovoltaic effect to convert solar energy into electrical energy.

[0003] Cadmium telluride thin film solar cells are an advanced photovoltaic (PV) technology, a thin film solar cell based on a heterojunction of p-type cadmium telluride and an n-type window layer. CdTe is a good photovoltaic material that matches the solar spectrum very well and is suitable for photoelectric energy conversion. It has a high theoretical efficiency. Among them, polycrystalline CdTe photovoltaic devices are one of the most successful commercial thin film solar cell technologies, and are favored because of their high efficiency, low cost and ease of manufacturing. However, despite the current density (J SC ) has almost reached its limit, the open circuit voltage (V OC The open circuit voltage is the highest voltage that a solar cell can generate without a load, and it is one of the key factors affecting the overall performance of the cell. Summary of the invention

[0004] In order to overcome the shortcomings of the prior art, the present invention provides a method for preparing a halogen-doped window layer and a cadmium telluride solar cell, which makes the window layer film become more n-type, increases the built-in electric field between the window layer and the p-type cadmium telluride film, and enables the halogen-doped thin film battery device to have a more effective charge separation, transmission and collection process, thereby increasing the open circuit voltage of the battery device.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is a method for preparing a halogen-doped window layer, comprising:

[0006] Obtaining a powder mixture consisting of cadmium halide powder and cadmium selenide powder; wherein the content of cadmium halide powder in the powder mixture is: 0.1-15wt.%;

[0007] Under the protection of nitrogen, the obtained powder mixture is placed in a mold, and then the mold is placed in a hot pressing furnace, and the hot pressing furnace is evacuated to make the air pressure in the hot pressing furnace less than 0.01Pa, and an inert gas is introduced for gas replacement. After the gas replacement is completed, the hot pressing furnace is heated to 300-1200°C at a rate of 5-15°C / min, and the hot pressing furnace is pressurized. When the air pressure in the hot pressing furnace reaches 40-100MPa, it is kept at this pressure for 50-150min, and then the temperature and pressure are reduced to room temperature and normal pressure, and the mold is taken out from the hot pressing furnace to obtain a halogen-doped window layer material;

[0008] The halogen-doped window layer material is sputtered or deposited onto the high-resistance buffer layer by magnetron sputtering or close-space sublimation deposition to obtain the window layer.

[0009] Furthermore, the cadmium halide powder includes one or more of CdF2 powder, CdCl2 powder, CdBr2 powder and CdI2 powder.

[0010] Furthermore, the content of cadmium halide powder in the powder mixture is 7 wt.%.

[0011] Furthermore, when the inert gas replacement is performed, the number of inert gas replacements is three times. After three inert gas replacements, inert gas is introduced into the hot pressing furnace to complete the final replacement of the inert gas.

[0012] Furthermore, the hot pressing furnace was heated to 650°C at a rate of 10°C / min and then pressurized. When the gas pressure in the hot pressing furnace reached 100 MPa, it was kept at this pressure for 90 minutes, then cooled and reduced in pressure to room temperature and atmospheric pressure, and the mold was taken out of the hot pressing furnace to obtain a halogen-doped window layer material.

[0013] A cadmium telluride solar cell comprises a window layer, wherein the window layer is made by a preparation method of a halogen-doped window layer.

[0014] Furthermore, it also includes a substrate layer, a transparent conductive oxide layer, a high-resistance buffer layer, a window layer, an absorption layer, a back contact layer and a back electrode layer arranged from bottom to top, wherein the thickness of the window layer is 30nm-150nm.

[0015] A method for preparing a cadmium telluride solar cell, comprising:

[0016] Arranging a transparent conductive oxide layer on the substrate layer to form a FTO substrate, and completing cleaning of the obtained FTO base layer;

[0017] A layer of tin dioxide is deposited on the FTO substrate by magnetron sputtering to obtain a high-resistance buffer layer;

[0018] Depositing a window layer material on the high-resistance buffer layer by magnetron sputtering or spatial sublimation to obtain a window layer;

[0019] A layer of cadmium telluride is deposited on the window layer by using a space sublimation method or a vapor transport deposition method to obtain an absorption layer, wherein the thickness of the absorption layer is 0.2-10 um;

[0020] A back contact layer and a back electrode layer are sequentially deposited on the absorption layer to obtain a thin film solar cell.

[0021] Furthermore, after the deposition of the absorption layer is completed, CdCl2 solution is sprayed on the absorption layer, treated in a nitrogen atmosphere at 400°C for 30 minutes, then etched with a phosphorus nitric acid solution for 10 seconds, rinsed with ultrapure water, and blown dry with nitrogen to complete the treatment of the absorption layer.

[0022] Furthermore, the absorption layer is a cadmium telluride absorption layer.

[0023] The specific beneficial effects of the present invention are:

[0024] Halogen is doped in the window layer material made by the method provided in the present application, so that the window layer film becomes n-type, and the built-in electric field between it and the p-type cadmium telluride film is increased, so that the halogen-doped thin film battery device has a more effective charge separation, transmission and collection process, thereby increasing the open circuit voltage of the battery device. This strategy can not only improve the open circuit voltage of the battery, but also effectively improve the photoelectric conversion efficiency of the battery device. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiment of the present invention and its design scheme, the following briefly introduces the drawings required for this embodiment. The drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 It is a schematic diagram of the cross-sectional structure of a thin-film solar cell in an embodiment of the present invention. DETAILED DESCRIPTION

[0027] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present application will be further described in detail below with reference to the accompanying drawings.

[0028] When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Instead, they are only examples of devices and methods consistent with some aspects of the present application as detailed in the attached claims.

[0029] Example 1

[0030] like Figure 1 The embodiment shown provides a cadmium telluride solar cell, which includes a substrate layer, a transparent conductive oxide layer, a high-resistance buffer layer, a window layer, an absorption layer, a back contact layer and a back electrode layer arranged from bottom to top;

[0031] In this embodiment, the substrate layer is made of soda-lime glass or borosilicate glass; the transparent conductive oxide layer is one or more of a fluorine-doped tin oxide layer, an indium-doped zinc oxide layer, and an aluminum-doped zinc oxide layer; the high-resistance buffer layer is one or more of a tin oxide layer, a zinc oxide layer, a magnesium-doped zinc oxide layer, and a fluorine-doped tin oxide layer;

[0032] The material of the window layer is one or more of fluorine-doped n-type CdSe, chlorine-doped n-type CdSe, bromine-doped n-type CdSe or iodine-doped n-type CdSe;

[0033] The absorption layer is a cadmium telluride layer; the back contact layer is one or more of a copper-containing carbon paste layer, a copper-containing zinc telluride layer, a zinc telluride layer, a tellurium layer or a cadmium zinc telluride layer; the material of the back electrode layer is one or more of aluminum, silver, gold, copper, nickel and titanium.

[0034] The method for preparing a cadmium telluride solar cell includes:

[0035] Step 1. Arrange a transparent conductive oxide layer on a substrate layer to form an FTO substrate, and clean the obtained FTO base layer; specifically, arrange a layer of one of a fluorine-doped tin oxide layer, an indium-doped zinc oxide layer, and an aluminum-doped zinc oxide layer on soda-lime glass or borosilicate glass to form an FTO substrate;

[0036] Step 2. The FTO substrate was then ultrasonically cleaned with a glass cleaner for 20 minutes, then ultrasonically cleaned with ultrapure water twice, each time for 20 minutes, and finally ultrasonically cleaned with ethanol for 20 minutes, and then dried in an oven at 100°C for 20 minutes;

[0037] Step 3. Preparation of a high-resistance buffer layer: depositing a layer of SnO2, zinc oxide, magnesium-doped zinc oxide or fluorine-doped tin oxide on the FTO substrate by magnetron sputtering to form a high-resistance buffer layer;

[0038] Step 4. Preparation of a window layer. The window layer in this embodiment is an n-type window layer. During preparation, one or more of the prepared fluorine-doped n-type CdSe, chlorine-doped n-type CdSe, bromine-doped n-type CdSe or iodine-doped n-type CdSe is deposited on the high-resistance buffer layer by magnetron sputtering or close-space sublimation to form an n-type window layer. The thickness of the n-type window layer is in the range of 30 nm to 150 nm, and is 80 nm in this embodiment.

[0039] Step 5. Preparation of the absorption layer. The absorption layer prepared in this embodiment is a p-type CdTe absorption layer. During the preparation, cadmium telluride is deposited on the n-type window layer using close space sublimation (CSS) or vapor transport deposition (VTD) to form a p-type cadmium telluride film with a thickness ranging from 0.2 μm to 10 μm. The thickness is preferably 3 μm in this embodiment. Then, CdCl2 solution is sprayed on the cadmium telluride film, treated at 400°C in a nitrogen atmosphere for 30 minutes, then etched with a phosphorus nitric acid solution for 10 seconds, rinsed with ultrapure water, and dried with nitrogen to obtain the absorption layer.

[0040] Step 6. Preparation of a back contact layer: depositing a copper-containing carbon slurry layer, a copper-containing zinc telluride layer, or a zinc telluride layer on the p-type CdTe absorption layer by magnetron sputtering or thermal evaporation to form a back contact layer;

[0041] Step 7. Preparation of the back electrode layer: depositing a back electrode layer on the back contact layer by magnetron sputtering, evaporation or screen printing to complete the preparation of the entire cadmium telluride solar cell.

[0042] Example 2

[0043] Based on Example 1, this example provides a method for preparing a fluorine-doped n-type CdSe material, comprising:

[0044] Obtain a powder mixture consisting of CdF2 powder and cadmium selenide powder; wherein the content of CdF2 powder in the powder mixture is: 0.1-15wt.%; in this embodiment, the content of CdF2 powder is 7wt.%;

[0045] Under the protection of nitrogen, the obtained powder mixture is placed in a mold; specifically, in a nitrogen environment, the mixed powder is placed in a mold for making fluorine-doped n-type CdSe material;

[0046] The mold is placed in a hot pressing furnace, and the hot pressing furnace is evacuated to make the air pressure in the hot pressing furnace less than 0.01Pa. In this embodiment, the air pressure in the hot pressing furnace is 0.005Pa after evacuation, and an inert gas is introduced for gas replacement. When the inert gas replacement is performed, the number of replacements is at least 3 times. After completing 3 replacements, an inert gas is introduced into the hot pressing furnace for the last time to complete the gas replacement in the hot pressing furnace. The inert gas in this embodiment is helium;

[0047] After the gas replacement is completed, the hot pressing furnace is heated at a rate of 5-15°C / min. The heating rate used in this embodiment is 10°C / min. According to this heating rate, when the temperature in the hot pressing furnace reaches 300-1200°C, and the temperature in the hot pressing furnace in this embodiment is 650°C, the hot pressing furnace is pressurized. In this embodiment, inert gas is used for pressurization. When the gas pressure in the hot pressing furnace reaches 40-100MPa, pressurization is stopped. In this embodiment, the gas pressure of the preferred hot pressing furnace reaches 100MPa, and pressurization is stopped, and the pressure and temperature are kept at this pressure and temperature for 50-150min. The keeping time of this embodiment is 90min. After the insulation is completed, the hot pressing furnace is depressurized and cooled. After the temperature drops to the heating state and the pressure drops to normal pressure, the mold is taken out from the hot pressing furnace to obtain fluorine-doped n-type CdSe material.

[0048] Example 3

[0049] Based on Example 1, this example provides a method for preparing a chlorine-doped n-type CdSe material, comprising:

[0050] Obtain a powder mixture consisting of CdCl2 powder and cadmium selenide powder; wherein the content of CdCl2 powder in the powder mixture is: 0.1-15wt.%; in this embodiment, the content of CdCl2 powder is 15wt.%;

[0051] Under the protection of nitrogen, the obtained powder mixture is placed in a mold; specifically, in a nitrogen environment, the mixed powder is placed in a mold for making chlorine-doped n-type CdSe material;

[0052] The mold is placed in a hot pressing furnace, and the hot pressing furnace is evacuated to make the air pressure in the hot pressing furnace less than 0.01Pa. In this embodiment, after evacuation, the air pressure in the hot pressing furnace is 0.002Pa, and an inert gas is introduced for gas replacement. When the inert gas replacement is performed, the number of replacements is at least 3 times. After completing 3 replacements, an inert gas is introduced into the hot pressing furnace for the last time to complete the gas replacement in the hot pressing furnace. The inert gas in this embodiment is helium;

[0053] After the gas replacement is completed, the hot pressing furnace is heated at a rate of 5-15°C / min. The heating rate used in this embodiment is 5°C / min. According to this heating rate, when the temperature in the hot pressing furnace reaches 300-1200°C, the temperature in the hot pressing furnace in this embodiment is 300°C, and the hot pressing furnace is pressurized. In this embodiment, inert gas is used for pressurization. When the gas pressure in the hot pressing furnace reaches 40-100MPa, pressurization is stopped. In this embodiment, the gas pressure of the preferred hot pressing furnace reaches 40MPa, and pressurization is stopped. The pressure and temperature are kept at this pressure and temperature for 50-150min. The insulation time in this embodiment is 150min. After the insulation is completed, the hot pressing furnace is depressurized and cooled. After the temperature drops to the heated state and the pressure drops to normal pressure, the mold is taken out from the hot pressing furnace to obtain a chlorine-doped n-type CdSe material.

[0054] Example 4

[0055] Based on Example 1, this example provides a method for preparing a bromine-doped n-type CdSe material, comprising:

[0056] Obtain a powder mixture consisting of CdBr2 powder and cadmium selenide powder; wherein the content of CdBr2 powder in the powder mixture is: 0.1-15wt.%; in this embodiment, the content of CdBr2 powder is 0.1wt.%;

[0057] Under the protection of nitrogen, the obtained powder mixture is placed in a mold; specifically, in a nitrogen environment, the mixed powder is placed in a mold for making a bromine-doped n-type CdSe material;

[0058] The mold is placed in a hot pressing furnace, and the hot pressing furnace is evacuated to make the air pressure in the hot pressing furnace less than 0.01Pa. In this embodiment, after evacuation, the air pressure in the hot pressing furnace is 0.008Pa, and an inert gas is introduced for gas replacement. When the inert gas replacement is performed, the number of replacements is at least 3 times. After completing 3 replacements, an inert gas is introduced into the hot pressing furnace for the last time to complete the gas replacement in the hot pressing furnace. The inert gas in this embodiment is helium;

[0059] After the gas replacement is completed, the hot pressing furnace is heated at a rate of 5-15°C / min. The heating rate used in this embodiment is 15°C / min. According to this heating rate, when the temperature in the hot pressing furnace reaches 300-1200°C, and the temperature in the hot pressing furnace in this embodiment is 1200°C, the hot pressing furnace is pressurized. In this embodiment, inert gas is used for pressurization. When the gas pressure in the hot pressing furnace reaches 40-100MPa, pressurization is stopped. In this embodiment, the gas pressure of the preferred hot pressing furnace reaches 70MPa, and pressurization is stopped. The pressure and temperature are kept at this pressure and temperature for 50-150min. The keeping time of this embodiment is 50min. After the insulation is completed, the hot pressing furnace is depressurized and cooled. After the temperature drops to the heating state and the pressure drops to normal pressure, the mold is taken out from the hot pressing furnace to obtain a bromine-doped n-type CdSe material.

[0060] Example 5

[0061] Based on Example 1, this example provides a method for preparing an iodine-doped n-type CdSe material, comprising:

[0062] Obtain a powder mixture consisting of CdI2 powder and cadmium selenide powder; wherein the content of CdI2 powder in the powder mixture is: 0.1-15wt.%; in this embodiment, the content of CdBr2 powder is 5wt.%;

[0063] Under the protection of nitrogen, the obtained powder mixture is placed in a mold; specifically, in a nitrogen environment, the mixed powder is placed in a mold for making iodine-doped n-type CdSe material;

[0064] The mold is placed in a hot pressing furnace, and the hot pressing furnace is evacuated to make the air pressure in the hot pressing furnace less than 0.01Pa. In this embodiment, after evacuation, the air pressure in the hot pressing furnace is 0.003Pa, and an inert gas is introduced for gas replacement. When the inert gas replacement is performed, the number of replacements is at least 3 times. After completing 3 replacements, an inert gas is introduced into the hot pressing furnace for the last time to complete the gas replacement in the hot pressing furnace. The inert gas in this embodiment is helium;

[0065] After the gas replacement is completed, the hot pressing furnace is heated at a rate of 5-15°C / min. The heating rate used in this embodiment is 8°C / min. According to this heating rate, when the temperature in the hot pressing furnace reaches 300-1200°C, and the temperature in the hot pressing furnace in this embodiment reaches 800°C, the hot pressing furnace is pressurized. In this embodiment, inert gas is used for pressurization. When the gas pressure in the hot pressing furnace reaches 40-100MPa, pressurization is stopped. In this embodiment, the gas pressure of the preferred hot pressing furnace reaches 90MPa, and pressurization is stopped. The pressure and temperature are kept at this pressure and temperature for 50-150min. The insulation time in this embodiment is 120min. After the insulation is completed, the hot pressing furnace is depressurized and cooled. After the temperature drops to the heated state and the pressure drops to normal pressure, the mold is taken out from the hot pressing furnace to obtain iodine-doped n-type CdSe material.

[0066] Comparative Example

[0067] This comparative example provides a method for preparing a cadmium telluride thin film solar cell, comprising:

[0068] Step 1. Arrange a transparent conductive oxide layer on a substrate layer to form an FTO substrate, and clean the obtained FTO base layer; specifically, arrange a layer of one of a fluorine-doped tin oxide layer, an indium-doped zinc oxide layer, and an aluminum-doped zinc oxide layer on soda-lime glass or borosilicate glass to form an FTO substrate;

[0069] Step 2. The FTO substrate was then ultrasonically cleaned with a glass cleaner for 20 minutes, then ultrasonically cleaned with ultrapure water twice, each time for 20 minutes, and finally ultrasonically cleaned with ethanol for 20 minutes, and then dried in an oven at 100°C for 20 minutes;

[0070] Step 3. Preparation of a high-resistance buffer layer: depositing a layer of SnO2, zinc oxide, magnesium-doped zinc oxide or fluorine-doped tin oxide on the FTO substrate by magnetron sputtering to form a high-resistance buffer layer;

[0071] Step 4. Preparation of the window layer: depositing an undoped window layer material film on the high-resistance buffer layer by magnetron sputtering or close-space sublimation to form an n-type window layer film with a thickness ranging from 30 nm to 150 nm, and 80 nm in this embodiment;

[0072] Step 5. Preparation of the absorption layer. The absorption layer prepared in this embodiment is a p-type CdTe absorption layer. During the preparation, cadmium telluride is deposited on the n-type window layer using close space sublimation (CSS) or vapor transport deposition (VTD) to form a p-type cadmium telluride film with a thickness ranging from 0.2 μm to 10 μm. The thickness is preferably 3 μm in this embodiment. Then, CdCl2 solution is sprayed on the cadmium telluride film, treated at 400°C in a nitrogen atmosphere for 30 minutes, then etched with a phosphorus nitric acid solution for 10 seconds, rinsed with ultrapure water, and dried with nitrogen to obtain the absorption layer.

[0073] Step 6. Preparation of a back contact layer: depositing a copper-containing carbon slurry layer, a copper-containing zinc telluride layer or a zinc telluride layer on the p-type CdTe absorption layer by magnetron sputtering or thermal evaporation to form a back contact layer;

[0074] Step 7. Preparation of the back electrode layer: depositing a back electrode layer on the back contact layer by magnetron sputtering, evaporation or screen printing to complete the preparation of the entire cadmium telluride thin film solar cell.

[0075] It can be seen that the biggest difference between the solar cell prepared in the comparative example and the solar cell prepared in Example 1 in the present application is that the comparative example uses an undoped window layer material film when preparing the window layer, while the window layer in the present application uses a film made of one or more of fluorine-doped n-type CdSe, chlorine-doped n-type CdSe, bromine-doped n-type CdSe or iodine-doped n-type CdSe as the window layer.

[0076] At the same time, the fluorine-doped n-type CdSe, chlorine-doped n-type CdSe, bromine-doped n-type CdSe and iodine-doped n-type CdSe materials prepared in Examples 2 to 5 were used as window layer materials to prepare Battery 1, Battery 2, Battery 3 and Battery 4, and the performance of the comparative battery prepared in the comparative example was tested. During the test, the open circuit voltage, short circuit current, fill factor and photoelectric conversion efficiency were tested. The specific test performance parameter data are shown in the following table:

[0077]

[0078] It can be seen from the above parameter data table that the materials made in Examples 2 to 5 of the present application can be used as the window layer of the solar cell, which can effectively improve the built-in electric field of the battery, promote the separation, extraction and transmission of carriers in the thin film, increase the open circuit voltage of the battery, and further improve the conversion efficiency of the solar cell.

[0079] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A method for preparing a halogen-doped window layer, characterized in that: include: Obtaining a powder mixture consisting of cadmium halide powder and cadmium selenide powder; wherein the content of cadmium halide powder in the powder mixture is: 0.1-15wt.%; Under the protection of nitrogen, the obtained powder mixture is placed in a mold, and then the mold is placed in a hot pressing furnace, and the hot pressing furnace is evacuated to make the air pressure in the hot pressing furnace less than 0.01Pa, and an inert gas is introduced for gas replacement. After the gas replacement is completed, the hot pressing furnace is heated to 300-1200°C at a rate of 5-15°C / min, and the hot pressing furnace is pressurized. When the air pressure in the hot pressing furnace reaches 40-100MPa, it is kept at this pressure for 50-150min, and then the temperature and pressure are reduced to room temperature and normal pressure, and the mold is taken out from the hot pressing furnace to obtain a halogen-doped window layer material; The halogen-doped window layer material is sputtered or deposited onto the high-resistance buffer layer by magnetron sputtering or close-space sublimation deposition to obtain the window layer.

2. The method for preparing a halogen-doped window layer according to claim 1, characterized in that: The cadmium halide powder includes one or more of CdF2 powder, CdCl2 powder, CdBr2 powder and CdI2 powder.

3. The method for preparing a halogen-doped window layer according to claim 1, characterized in that: The content of cadmium halide powder in the powder mixture is: 7 wt.%.

4. The method for preparing a halogen-doped window layer according to claim 1, characterized in that: When the inert gas replacement is performed, the number of inert gas replacements is three times. After three inert gas replacements, inert gas is introduced into the hot pressing furnace to complete the final replacement of the inert gas.

5. The method for preparing a halogen-doped window layer according to claim 1, characterized in that: The hot pressing furnace was heated to 650°C at a rate of 10°C / min and then pressurized. When the gas pressure in the hot pressing furnace reached 100MPa, it was kept at this pressure for 90 minutes, then cooled and reduced in pressure to room temperature and atmospheric pressure, and the mold was taken out of the hot pressing furnace to obtain a halogen-doped window layer material.

6. A cadmium telluride solar cell, characterized in that: The invention comprises a window layer, wherein the window layer is made by the preparation method of a halogen-doped window layer according to any one of claims 1-5.

7. The cadmium telluride solar cell according to claim 6, characterized in that: It also includes a substrate layer, a transparent conductive oxide layer, a high-resistance buffer layer, a window layer, an absorption layer, a back contact layer and a back electrode layer arranged from bottom to top, wherein the thickness of the window layer is 30nm-150nm.

8. A method for preparing a cadmium telluride solar cell, characterized in that: include: Arranging a transparent conductive oxide layer on the substrate layer to form a FTO substrate, and completing cleaning of the obtained FTO base layer; A layer of tin dioxide is deposited on the FTO substrate by magnetron sputtering to obtain a high-resistance buffer layer; Depositing a window layer material on the high-resistance buffer layer by magnetron sputtering or spatial sublimation to obtain a window layer; A layer of cadmium telluride is deposited on the window layer by using a space sublimation method or a vapor transport deposition method to obtain an absorption layer, wherein the thickness of the absorption layer is 0.2-10 um; A back contact layer and a back electrode layer are sequentially deposited on the absorption layer to obtain a thin film solar cell.

9. The method for preparing a cadmium telluride solar cell according to claim 8, characterized in that: After the deposition of the absorption layer is completed, CdCl2 solution is sprayed on the absorption layer, treated in a nitrogen atmosphere at 400°C for 30 minutes, then etched with a phosphorus nitric acid solution for 10 seconds, rinsed with ultrapure water, and blown dry with nitrogen to complete the treatment of the absorption layer.

10. The method for preparing a cadmium telluride solar cell according to claim 8 or 9, characterized in that: The absorption layer is a cadmium telluride absorption layer.

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